Colours of Eggs 



"5. Many birds lay eggs which exhibit very 

 great variations. 



"6. Some birds lay eggs of different types, 

 and these sometimes differ from one another so 

 greatly that it is difficult to believe that they 

 could have been laid by the same species." 1 



7. It not infrequently happens that one species 

 lays in the disused nest of another, and the eggs 

 of the latter are often very different in colouring 

 from those of the former. 



We have up to the present considered the theory 

 of general cryptic colouration, which declares that 

 the majority of creatures are so coloured as to be 

 inconspicuous. We have still to deal with the 

 hypothesis of special cryptic colouring. 



Certain animals look, when resting, very like 

 an inanimate object, such as a dead leaf or a 

 twig. This resemblance is said to be the result 

 of natural selection, since it enables its possessors 

 to escape destruction ; they are seen, but mis- 

 taken for something else. 



The classical examples of this kind of protec- 

 tive colouring are furnished by the Kallimas or 

 leaf-butterflies, which display an extraordinary 

 resemblance to dead leaves. 



Other examples are the stick-insects and the 

 lappet moth, which looks like a bunch of dry 

 leaves. It is needless to multiply instances. 



1 Journal of the Bombay Natural History Society, VoL xv. 

 1903-4)) P- 454- 



O 209 



